Valve-seat for steam-engines



I UNITED STATES PATENT OEEICEN RETAS BLOOD, OF MANCHESTER, NEW HAMPSHIRE.

VALVE-SEAT FORlSTEAM-ENGINES.

SPECIFICATION formingpart of Letters Patent No. 252,012, dated January 10, 1882.

Application filed November 10, 1879.

To all whom it may concern: I

Beit known that I, ARE'rAs BLooD, of Manchester, county of Hillsborough, State of N ew Hampshire, have invented an Improvement in Valve-Seats for Steam-Engines, of which the following description, in connection with the accompanying drawings, is a specification.

My invention relates to steam-engines, and

has for its object to render, by a simple and in-` for use in locomotives.

The valve and its seat in locomotives and smallstationary engines are usually ofthe 'same material-nam ely, cast-iron..

I have `ascertained by experiment that by making asmall-portion ofthe Wearingsuriare of the valve-seat of a different material having a different-grain or texture the wear is gre-atl y diminished and an engine will run a much longer time Without the. necessity of dressing oft' the valve-seat. y

To add thisdifferent metal in a proper manner is the object of my invention, which consists in providing a valve-seat with two strips or. tenons of metal, preferably ot' brass or an alloy of similar nature, of about the same hardness as, or harder than, the valve-seat, but of different nature or texture, arranged in grooves across the valve-seat-th atis, with their length at right angles with the direction in which the valve movesand preferably placed just outside of the induction-ports', and in order that the surface of said strips may not be broken by screw-holes I make sad strips of dovetail or other irregular-sided shape in cross-section, and undercut the grooves to correspond, whereby said strips may be driven in place longitudinally and retained securely in position, yet be so held that they may be readily struck and driven out when it is desired torenew them.

I do not broadly claim metals of two differsome different forms of cross-section for the metal strip.

The cylinder a, induction-ports b, and exhaust-port c are all of usual construction.

The valve-seat d is provided withlong grooves e, placed just outside the induction-ports b, where the wear is greatest, which are preferably of dovetail shape, as shownthat is, larger at the bottom than at the top. The metal tenons or strips are shaped tojust tit thegroovesl c, into which they are driven longitudinally, as shown by the arrow, Fig. 1, and there held, on account of their shape, unable to be removed from said grooves otherwisethan. longitudinaily.l The wear or abrasive action vbetween the valve of cast-iron andthe strips of brass, or an alloy of similar nature, or steel, is much less than if the two bodies were both of the same material, as castiron.

The shape of cross-section of the grooves and tenons may be varied, as shown at Fig. 4, the essential feature being that their wearing-faces be fiat, and that when inserted in the grooves they cannot be taken therefrom, except by being moved transversely across the valve-seat, or so that their tops are smaller than their bot'- toms,so that the tenons are prevented from anymovement other than longitudinal. In use they are prevented from longitudinal movement by the sides of the steam-chest, which abuts against their ends. A

I am aware that linings of soft metal have been used to diminish friction; but such could not answer as a substitute for the Vtenons of hard metal used by me, the object of which is to reduce the wear or abrasive action rather than the friction. y

I am also aware that portions of different metal have been embeddedin a surface exposed to wear by casting the main body of the metal around such embedded` portions; but such a method is not applicable to a valve-seat, and

IOO

the said portions are not removable nor espa-- ble of being replaced by others when desired,

as in the present invention.

I claim-a 5 The combination, with the slide-valve, of the valve-seat and its ports, the said valve-sent being provided with transverse grooves undereut or dovetaibshaped in cross-section, as described, eombined with independent strips or 1o' tenons fitted to slide longitudinally in the said grooves, substantially as and for the purpose set forth.

In testimony whereof have signed my name to this specification in the presence oftwo subseribing Witnesses.

ARETAS BLOOD.

Witnesses:

G. W. GREGORY, N. E. C. WHITNEY. 

